In so called mobile bindings which are intended to hold a series of reviews together, these latter may be held in position by S shaped elements one leg of which is engaged in the central fold of a review, the other leg being fixed to the back of the review.
Some mobile bindings comprising S shaped holding elements are formed from two sheets of cardboard, or a similar semi rigid material, which extend over the whole length of the binding and which are bonded one to the other, except at least in the end portions of the back, the inner sheet having an opening in which one of the end legs of the S shaped element may be engaged, the other end being then engaged in the middle of a review to be bound.
Experience has shown that, when the binding comprises a relatively large number of reviews, the inner sheet of the back moves away from the outer sheet and the holding elements risk breaking loose from the binding.
The present invention provides then a mobile binding of the above type improved so as to overcome this drawback.